{"id":"F2006B01799","name":"AD/A109/15 - Modification of Overhead Console Relay Boards","slug":"ad-a109-15-modification-of-overhead-console-relay-boards","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":40997,"registerId":"commonwealth-F2006B01799-current","compilationNumber":null,"startDate":"2026-04-01","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/A109/15 - Modification of Overhead Console Relay Boards","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-description: CASA Airworthiness Directive\nmeta-generator: Aspose.Words for .NET 22.10.0\nmeta-keywords: Issue 1/1989,Rotorcraft,Agusta A109 Series Helicopters,Modification of Overhead Console Relay Boards,15\ntitle: Airworthiness Directive - AD/A109/15 - Modification of Overhead Console Relay Boards\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Agusta A109 Series Helicopters\n\n \n\nAD/A109/15 Modification of Overhead Console Relay Boards 1/89\n\nApplicability: All Agusta A109A and A109AII helicopters up to and including S/No 7400 with the exception of S/Nos 7187, 7366 and 7396.\n\n \n\nRequirement: Action in accordance with Mandatory Agusta Bollettino Tecnico No 109-73.\n\n \n\nCompliance: On replacement of GCU box in accordance with the Requirement document, but in any case, prior to 26 January 1990.\n\n \n\nBackground: Lear Siegler Inc. introduced some minor modification to the GCU box P/N 51509- 002R which in some cases, when installed in A109 aircraft, has caused non operation of both No 1 and No 2 generators.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2303},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive maintains a narrow, targeted scope focused solely on the specific relay board modification required to prevent dual generator failure in the identified helicopter models. No expansion of scope beyond the original airworthiness safety intent."},"complexity_factors":["Single operative requirement contained in one sentence referencing an external technical document (Agusta Bollettino Tecnico No 109-73)","Three specific serial number exemptions in the applicability clause (S/Nos 7187, 7366, and 7396)","No interpretation section, defined terms, or nested conditional provisions"],"plain_english_summary":"**What this does:** This is a mandatory safety order requiring a specific electrical modification on certain Agusta helicopters to prevent a dangerous dual generator failure.\n\n**Who it affects:** Owners and operators of Agusta A109A and A109AII helicopters with serial numbers up to 7400 (excluding serial numbers 7187, 7366, and 7396).\n\n**What you must do:** Whenever you replace the GCU (Generator Control Unit) box, you must modify the overhead console relay boards by following the instructions in Agusta's Technical Bulletin No. 109-73.\n\n**Why it matters:** A modified GCU box (part number 51509-002R) manufactured by Lear Siegler can cause both the No. 1 and No. 2 generators to stop working simultaneously, potentially leading to complete electrical failure during flight.\n\n**Compliance deadline:** This modification had to be completed before 26 January 1990, or immediately upon replacing the GCU box if that occurred earlier."}},"importantCases":[],"_links":{"self":"/api/acts/ad-a109-15-modification-of-overhead-console-relay-boards","history":"/api/acts/ad-a109-15-modification-of-overhead-console-relay-boards/history","analysis":"/api/acts/ad-a109-15-modification-of-overhead-console-relay-boards/analysis","conflicts":"/api/acts/ad-a109-15-modification-of-overhead-console-relay-boards/conflicts","importantCases":"/api/acts/ad-a109-15-modification-of-overhead-console-relay-boards/important-cases","documents":"/api/acts/ad-a109-15-modification-of-overhead-console-relay-boards/documents"}}